For the jaded traveler, arrival in one place in Japan can often seem suspiciously like arrival in any other. After quitting a station building, you can find yourself viewing thoroughfares lined with familiar-looking stores, with it all appearing instantly similar to other places beheld elsewhere the length and breadth of the archipelago. But that deja vu sensation certainly doesn’t manifest itself in the Yaeyama Islands.

The usual arrival point in this island group at the remote end of the long Okinawan archipelago is the airport on the main island of Ishigaki. The drive from the airport is along roads flanked with palm trees, past fields of tall sugarcane and stone-walled gardens bristling with crimson hibiscus. From Ishigaki’s port, Iriomote is 40 minutes by ferry.

Iriomote is the largest of the Yaeyama Islands, which are the least Japan-like places in the national territory. Taiwan is much nearer than the main island of Okinawa; the Philippines are closer than Kyushu. The Tropic of Cancer is just 100 km away, and so the Yaeyamas are just a whisker away from being absolutely tropical. Bright varieties of tropical fruit are sold in markets; still brighter varieties of tropical fish dart through coral seas.

That stunning diversity of underwater life is certainly no secret among scuba divers, who come to the Yaeyamas to enjoy some of Japan’s best diving spots. At 20 km long and 15 km wide, the coral reef that extends from Iriomote to Ishigaki is the largest in the country.

Notable here is the strait between Iriomote and the nearby island of Kohama, which is known as the Manta Way — an appellation that derives from the fact that this is a favored transit passage for schools of gigantic 5-meter-long manta rays, prone to glide serenely through here from April to June.

Above water, Iriomote differs from the other Yaeyamas — and indeed most of Japan — in being one of those rare spots where nature palpably still retains the upper hand. Iriomote’s human population stands at a paltry 2,000, and habitation is confined to a tenuous stretch along the north and east coasts. Over 90 percent of this emphatically rugged island is covered by impenetrable primeval jungles of mangrove, banyan and palm trees, within which lurk leeches and pit vipers.

Despite its relative compactness — Iriomote is just a little smaller than Malta — it has remarkably high biodiversity, evident in the great variety of amphibians, reptiles, insects and birds seen on the island. Iriomote is home to Japan’s biggest lizard, its only tortoise, and many other species that are endemic to Iriomote or other Yaeyama islands.

Meanwhile, on one of Iriomote’s beaches it’s not hard to find hoshizuna (star sand), which results from the star-shaped calcareous skeletons of tiny creatures known as foraminifers, which thrive in coral seas.

Iriomote’s best-known creature by far, though, is its cat. With a population of perhaps just 100 or so individuals, the endangered wildcat is one of the world’s rarest felines. Nonetheless, it is a famed symbol of Iriomote, and so it is naturally not uncommon to hear visitors on tours voicing their hopes of glimpsing one. But since the scarce feline is not the outgoing type and Iriomote’s impenetrable forests are simply vast, tourists have about as much chance of espying the catty one as they do of spotting Elvis out there among the mangroves.

As might be supposed, the islanders are rather proud of their furry carnivore. An official guidebook refers to the creature not just as a cat but as the grander-sounding Iriomote lynx. And the sculptor who executed the image of the animal that stands outside the post office in the island’s southern port of Ohara depicted a formidable panther-sized brute that looks as though it has rather a soft spot for human jugulars. However, sadly for local pride, the Okinawan cat is in fact no bigger than the thing that coughs up hairballs on your carpet.

Iriomote’s cat was not actually discovered until 1965, which may seem a tad late for such a fair-sized animal, but then for the most part there weren’t too many people around on Iriomote to be doing any spotting. Until its eradication after World War II, malaria infested the island, and historically that worked as quite an impediment for human habitation. A significant population influx did, however, occur in the late 19th century, when coal was mined on the island using indentured laborers brought there and forced to work in appalling conditions.

That port where the cat sculptor exhibits his handiwork is the busiest one on the island, though “busy” has to be understood in the Iriomote scheme of things. Get away from Ohara’s harbor, and humans are about as common as wildcats in this sleepiest of villages. It is from Ohara that trips can be made up the mangrove-banked Nakama River, which is one of two large rivers that cross the island. And it would be an extremely rare visitor to Iriomote who did not take a trip up the Nakama or the longer Urauchi River, which carries the sobriquet of “Japan’s miniature Amazon.”

A favored stopping-off point on the trip up the Nakama allows visitors to inspect at close hand the unusual Heritiera littoralis — an odd-looking arboreal specimen that for some equally odd reason is called the Looking-glass Tree in English, and which grows here in one of its northernmost locations. Its ribbon-like root buttresses are distinctively curved, twisting affairs; its hard wood was once used for making ship’s rudders; it’s not the kind of thing you want to have in your garden.

Further upstream, the rivers change suddenly in character from phlegmatic, meandering waterways to wildly rushing torrents. In these upper stretches, Iriomote’s high rainfall finds dramatic expression in the spectacular waterfalls that constitute the most impressive sights on this lush island.

Iriomote lacks a hospital, a high school or a bank. Since it also lacks an airport, that ferry from Ishigaki is the only means of reaching the place. But isolation actually works in Iriomote’s favor. With visitor numbers already dangerously high for its delicate environment, the last thing Iriomote really needs is even more tourists.

Getting there: The southern port of Ohara can be reached in 40 minutes by ferry from Ishigaki; the northern port of Uehara can be reached in 45 minutes from Ishigaki.